thermostat differences

[adobong]

Hey guys, I got a question pertaining thermostats. what is the difference with a 60c vs. 71c thermostat in a outboard? is it something to do with fresh water temp and salt water temp, and locations? I'm assuming fresh water is colder in certain locations which you would use the 71c thermostat and warmer water like salt water in certain location and use the 60c thermostat. is this correct? if someone has a better understanding this would please share the knowledge thank you.

 

[adobong]

Hey guys, I got a question pertaining thermostats. what is the difference with a 60c vs. 71c thermostat in a outboard? is it something to do with fresh water temp and salt water temp, and locations? I'm assuming fresh water is colder in certain locations which you would use the 71c thermostat and warmer water like salt water in certain location and use the 60c thermostat. is this correct? if someone has a better understanding this would please share the knowledge thank you.

 

[boscoe99]

May I ask why you are asking your question?

Outboard motors run very cool vis a vis an automobile motor. For a particular reason. But sometimes it can run too cool and a four stroke might have a propensity to "make oil". A hotter thermostat can be used to help mitigate the making oil issue.

It generally has little to do with water temperature. Regardless of the water temperature the thermostat should maintain the engine water temperature at or about the thermostats rating.

 

[adobong]

i have a 2005 df140 zuke and with gradient overheats. i checked my cooling system and found nothing unusual so I'm doing process of elimination and am down to the thermostat which ive tested in a hot pot of water. now my manual says operating range is 136-144F but when i tested my current t-stat its opening at a higher temp (150F) which is a little higher than what my manual states. i found that there is two options of t-stat's and don't know which one it is. Since I'm the third owner of this motor and no history background I'm dead stuck trying to figure it out. I know t-stat are not based off of temp but if this t-stat is opening a little later or higher in temp which may be triggering a gradient overheat compare to a lower temp operation which will allow more water flow to earlier to help with the cooling and may be not trigger a gradient overheat. these are my thougts i may be wrong or not but need some ones else input on this to see if I'm on the right path. its to costly for me to send it to a boat shop that's why I'm trying to fix myself which i don't think its that complicated.

 

[adobong]

I'm assuming since the outboard came from freshwater/florida area which i think is colder waters maybe they installed a higher temp range t-stat. and since I live out here in Hawaii more warmer waters maybe this might be the cause. I'm not sure just my assumption.

 

[99yam40]

why do you think the water temp in Florida is colder than HI?
Florida is a lot closer to the equator and has a lot shallower waters around it

 

[adobong]

I bought the outboard from my coworker who purchased the boat with this outboard from the seller who lived in florida at the time. But originally the boat been used in mainly fresh water (Alabama) then they moved out to florida where they used it a few time before they sold it.

 

[99yam40]

that has nothing to do with the water temps in the different places, since you waters are colder than that in Florida

sounds like your coworker had a problem that they moved over to you now